A Golden Age for Aged Players

A few weeks ago I took a look at the performance of the league’s oldest players and how it compared to historical results. Now I’m back with more data!

While the data for the past ten seasons doesn’t have much of a pattern, when we include seasons dating back to 1978-79, there is definitely a more pronounced trend. In fact, now we can see that there was a golden age for the elder NBA player around 1996-97 to 2004-05. Interestingly, the two lock-out shortened seasons of 1998-99 and 2011-12 appear (for the moment) to be local maximums. Is there something about a lockout that makes older players more attractive to GMs? We’d need more data to know for sure, and although I hate lockouts, I’m sure we won’t have to wait all that long before we get that next data point.

This graph shows the minutes played by players aged 35+ by season, starting from 1978-79. Keep in mind that the lockout seasons, 1998-99 (21 on the graph) and 2011-12 (34 on the graph), are not corrected to reflect the decrease in total available minutes in those seasons; the same is also true of the current season (35 on the graph).

It’s clear from both these graphs that older players are playing a larger part in today’s NBA than they did during the 80s and early 90s. But to me the real question is: are they any more productive, and are this season’s older players playing better than we would expect?

But first: an interesting finding. When we check to see if there is a relationship between productivity and age, there is only a weak relationship, which is contrary to my previous finding. The graph above replicates the methodology from my previous post, but includes seasons from 1978-79 to 2012-13 instead of just the last ten years. However, there may be a problem with applying this methodology to older seasons; from 1978-79 to 1989-90, the average number of players aged 35+ was under five (in both 1980-81 and 1981-82, only Elvin Hayes made the cut). One or two players can have a significant impact on the average of such a small group. The solution is to ignore which season the players played in and to group them all together. When we do so, the relationship becomes even weaker (the R-squared is a minuscule 0.000445). Even if we add a filter for minutes played (400+, as always), the relationship remains weak (the R-squared is 0.00589) and the trendline is actually positive — which means that it actually has players becoming more productive past their 40s. Simply put, within the oldest NBA players, age does not do a good job of explaining productivity. This is probably due to survivorship bias and the fact that we are keeping track of WP48, not year-to-year decreases in individual WP48.

Despite this, it does seem that older players have been more productive in recent years.

In the past 14 seasons, older players have been consistently near the top of their historical range. While the ages have been within normal boundaries (odds of both populations being the same with respect to age: p = 0.237), the WP48s have been clearly different (odds of both populations being the same with respect to WP48: p = 0.00773). Furthermore, this difference has been driven by high productivity over the last five seasons.

Given this, I’d say that the league’s older players are indeed becoming more productive. Have they been exceptionally productive this season? Compared to the historical record, yes. But compared to the last five seasons, this season does not stand out. So it really depends on one’s perspective.

I don’t agree with Mark Cuban about many things, but he was pretty early in realizing that with modern training, nutrition, medicine etc… that current players can remain productive for a lot longer now than they could in the past. I recall reading some comments he made along those lines awhile back when talking about Jason Kidd and a few other players he was interested in despite their age.

It’s one thing to delay a player’s decline. It’s another thing when you see a form reversal from an older player without explanation. Players that were already in clear decline should not suddenly find the fountain of youth. So if we start seeing that kind of thing, it might mean something beside vitamins and minerals is in the Gatorade.

I did mention that the number of players in the league has changed over time in the previous post. It would have been more work, and ultimately I decided that it wouldn’t be worth it, given that there is a clear increase from one player in the entire league to multiple players per team.

If you would like to modify that graph with that additional information and create your own blog post, feel free! Just remember to link back to this post and attribute anything you take from someone else.

“Given this, I’d say that the league’s older players are indeed becoming more productive. Have they been exceptionally productive this season? Compared to the historical record, yes. But compared to the last five seasons, this season does not stand out.”

Uncomfortable question. In another sport a decade or two ago, older players–Bonds, McGuire, Clemons, etc—suddenly started defying long-established patterns of decline with age. We all know what drove it. Might doping be a possible factor? I’m fully prepared to believe that better diets and training methods are driving this trend. And I don’t think an older NBA player has pulled a Bonds—suddenly, at a late age, having a season that not only far outstripped the excellent standards of his own youthful prime, but also outstripped any performance, ever. But is this something we should be thinking about wrt to the NBA?

This post got me thinking even more so I drafted up a spreadsheet using the weighted average age (ie. min played per age / total mins played) and tried to find some patterns. Here are some things that I noticed:

1) We have waves of players that tilt the averages. ie. duncan, willis, stockton, barkley, garnett. Every couple of years you get a handful of these guys that just stick around.

2) The 3/4/5 positions have the longest careers on average.

3) Found that the rsq of pace factor against % of minutes played by over/under age 31 of 65%.

I’d like to take obv point 3 one step further and compare the league averages of shot allocation % for fta, and 3pa. I’d like to take a guess that the increase of 3pa’s is benefiting the older guys.

Just a note that point was league averages not individual team averages. I think if we drilled it down to team averages we’d get a higher rsq.

If KG was was playing in his usual PF position, he’d still be producing at an above-average level (albeit barely). Unfortunately he’s been playing C this year, and as such, has been playing against more productive players, which lowers his own WP48 (if you click on the ? you can change his position from C to PF).

But if you compare KG against his career numbers, it’s a slow decline in most areas. Rebounds, assists, and blocks are down. Turnovers and fouls haven’t really moved. His TS% is down, and while he is still above average in TS%, his attempts keep going down from both the field and the line. Shooting is what drives productivity, so that is the main reason he’s been less productive.

I could be wrong, but I don’t think that PEDs are playing a big part in this. As you say, these generally aren’t old guys posting unexpected numbers as they age — it’s mostly great players continuing to play at a high level up into their late 30s and early 40s. But even if this performance was due to PEDs…would that be such a bad thing? Who doesn’t love historically great players continuing to play well in their 40s?

Steven,

1) I also noticed the cohorts moving through the league and affecting the averages. You also see certain players who play until their legs fall off. I should have a post up with the Old Guy All-stars shortly.

2) I think that’s a matter of the short supply of tall people. The taller you are, the harder you are to replace, and therefore the longer you can stay in the league. Meanwhile, the shorter players face an ever increasing amount of younger, similarly-sized players in their competition for roster spots.

3) I would be searching for a cofactor there. I think it’s simply a coincidence that older players are playing more as the pace slows down. The 80s were awfully fast.